Abstract: Fuling shale gas field is the first shale gas field put into commercial development, with the largest proven reserves and the highest average test production in China. It was discovered on November 28, 2012, by Sinopec Exploration Company based on the theory of “binary enrichments” for highly-evolved marine share gas in complex structural areas in southern China. By the end of 2015, its total proven gas reserves were 3805.98×108m3, and the designed production capacity of 50×108m3 in Phase I was achieved. This gas field is characterized by integration of source and reservoir, intensive layered distribution and general gas endowment, It is a typical self-generation and self-storage shale gas field. As a mid-deep, high-pressure, and high-quality natural gas reservoir, it contains high-quality shales in deep-water continental shelf, with fine roof and floor conditions and weaker structural transformation in later stage, which are the major factors controlling shale gas enrichment and high productivity in this area. Based on the discovery of Fuling shale gas field and the exploration practices in the Sichuan Basin and its periphery, the main controlling factors for shale gas enrichment in complex structural areas in southern China were analyzed. The analysis highlighted the preservation condition as the key factor. Conclusions are drawn in three aspects. First, extra-basin tectonic uplifting time, syncline width, burial depth and fracture are the main parameters to evaluate the preservation conditions in shale gas layers. Second, for areas at the basin margins, the evaluation should focus on the effects of basin-controlling faults on shale gas layers. Third, nature and scale of the faults and development features of high-angle fractures in the basin are critical for evaluating the shale gas preservation conditions. From the discovery of Fuling shale gas field, the following enlightenments can be obtained for shale gas exploration in complex structures in southern China. First, shale gas exploration should be conducted depending on the basic laws of oil and gas generation. Second, several shale gas exploration targets exist in southern China, especially the regions deeper than 4500 m, extra-basin normal pressure regions, and continental shale gas areas. Third, basic information, innovative ideas and critical technologies are essential for making breakthroughs in shale gas exploration.

Key words: exploration and discovery history, gas pool features, preservation condition, enlightenment, Wufeng Fm-Longmaxi Fm, Fuling shale gas field